本研究利用線放電加工切削多晶鑽石 (Polycrystalline diamond)，並設計夾持治具配合操作參數進行切削。在L18田口實驗 (Taguchi method) 中，操作參數區間為開路電壓80-180 V、引弧電流 0.4-0.9 A、脈衝時間0.1-0.3 µs、脈衝休止時間10-20 µs對材料移除率 (Material removal rate)、表面粗糙度 (Surface roughness)、加工表面波動層 (Surface asperity) 及刀尖半徑 (Edge radius) 進行觀測。在變異數分析 (Analysis of Variance, ANOVA) 中，判斷參數對各項指標顯著性，並建議單一指標優化組合。此外，利用迴歸方程式 (Regression equations) 建立參數與指標之關係模型，在均等權重滿足各量化指標以達成綜合指標優化。實驗結果顯示在操作參數區間內較高的脈衝時間 (0.3 µs) 可以得到較高材料移除率 (22.9 mg/min)，較低的脈衝時間 (0.1 µs) 可以得到較佳的表面粗糙度 (Ra 1.42 µm)。綜合指標優化中，在操作參數於開路電壓126 V、引弧電流0.9 A、脈衝時間0.1 µs、脈衝休止時間20 µs之條件，演算模型與實驗值在各指標的比對之下，誤差在材料移除率為10.3%、表面粗糙度為3.04%、加工面波動層為26.09%。

This work is to evaluate the machining performance in multiple objectives when cutting of polycrystalline dick using wire electrode discharging method. The 2 μm polycrystalline with 8-15% cobalt having weak conductivity (1.8×10-4 (Ωm)-1) and necessitated a bespoke feature to couple with preferable parameter sets for discharging actions. In this experiment, the influences of open voltage (80-180 V), ignition intensity (0.4-0.9 A), pulse on-time (0.1-0.3 µs), pulse off-time (10-20 µs) on the material removal rate, surface roughness, surface asperity and edge radius was resolved with statistical methods (ANOVA) in an orthogonal array (Taguchi L18). The developed empirical model suggests the preferable parameter sets for the multi-objective optimization while equal weightings are given to each objective. The results suggest the high pulse on-time (0.3 µs) produce higher material removal rate (22.9 mg/min) and the lower pulse on-time (0.1 µs) produce lower surface roughness (Ra 1.42 µm) whilst the lower open voltage (80 V) leads to lower surface asperity (0.63µm) and small edge radius (32.6 µm) on the machined surface. When compared the experimental results to the modelling values, the least error for material removal rate, surface roughness and surface asperity are 10.3%、3.04%、26.09% respectively under the preferable parameters of open voltage (126 V), ignition intensity (0.9 A), pulse on-time (0.1 µs), and pulse off-time of (20 µs).

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